I've found that it tends to take off a lot faster, but every tank is different.

On my personal tank it took off like crazy, it went from zero to full coverage in about 8-10 days and I had a box full of algae in 14 days, but my tank might be "conditioned" already...seen it before but can't explain it scientifically

See the recent vids on my YouTube channel, link is in the video description. You'll see what I mean....

Also, the mortar layer is sacrificial, it tends to detach a little at a time - usually during cleaning. Then the canvas that becomes exposed starts the normal maturing process, a little at a time. That is a longer process.

A plain rouged up canvas screen can take 4-6 weeks or more to get full coverage. The mortar allows growth to get to that point usually in a week or two. Then the exposed canvas areas mature as they become exposed. So in effect, the mortar screen is like a 2-stage screen